This project includes several studies of the visual system in the brain of monkeys. More specifically, we studied brain mechanisms whereby the visual signals seen by the eye are translated into commands to initiate saccadic eye movements. We recorded electric responses from single nerve cells in the superior colliculus of an awake, trained monkey. The results from this study suggest that visual and eye movement information is integrated to implement rapid saccades. We made lesions in the two branches of the visual system in order to determine which brain structures are necessary to make accurate saccades. We have studied single nerve cell responses to visual stimuli in the pre-striate cortex, a later stage of visual processing than previously studied. We measured changes in visual excitability of nerve cells associated with saccades at the lateral geniculate nucleus.